14.7.9 @minus (-): Inserting a Minus Sign

Use the @minus{} command to generate a minus sign. In a
fixed-width font, this is a single hyphen, but in a proportional font,
the symbol is the customary length for a minus sign—a little longer
than a hyphen, shorter than an em-dash:

‘-’ is a minus sign generated with ‘@minus{}’,
‘-’ is a hyphen generated with the character ‘-’,
‘—’ is an em-dash for text.

In the fixed-width font used by Info, @minus{} is the same
as a hyphen.

You should not use @minus{} inside @code or
@example because the width distinction is not made in the
fixed-width font they use.

When you use @minus to specify the mark beginning each entry
in an itemized list, you do not need to type the braces
(see @itemize).

If you actually want to typeset some math that does a subtraction, it
is better to use @math. Then the regular ‘-’ character
produces a minus sign, as in @math{a-b} (see Inserting Math).